Traditionally, each transponder is associated with a single uplink service area and a single downlink service area. The disadvantage of such a scheme is that if traffic exists from two or more service areas to a given service area, several transponders are required for connectivity purposes, even if the total required capacity is compatible with that of a single transponder. This does not represent efficient or optimal use of the satellite resources, in terms of Radio Frequency resources (bandwidth) and power resources. Also, a conventional architecture associating a transponder with multiple service areas degrades the figure of merit (also called G/T) which, in the present case, is the relationship between the gain G of the antenna and the noise temperature T over the uplink service areas.
Additionally as the uplink service area increases in area the figure of merit G/T decreases.